Sulfoximines



ABSTRACT F THE DISCLOSURE Sulfoximines having one aliphatic hydrocarbon group of at least 30 carbon atoms find use as lubricating oil detergents.

This invention concerns novel sulfur and nitrogen containing derivatives which find use as additives in lubricating oils. More particularly, this invention concerns novel sulfur and nitrogen containing derivatives having a long hydrocarbon chain which find use as additives, particularly detergents, in lubricating oils.

A development of major importance in the lubricating oil additive field has been the introduction of ashless detergents; that is, metal free compounds which are capable of reducing varnish and sludge deposits in the engine. An important advantage of these ashless detergents is the avoidance of the ash formed by the metal salt detergents on decomposition. Thus, valve and combustion chamber deposition with accompanying octane requirement increase can be minimized through their use.

A variety of lower molecular weight ashless detergents have been reported in the patent literature. See for example U.S. Patent No. 3,018,251, which discloses acylated polyamines; 2,764,551, which discloses polyesters containing amino groups; 2,887,452, which discloses urethanes; and 2,371,333, which discloses esters of pentaerythritol.

It has now been found that compounds having the sulfoxi-mine functionality and a long hydrocarbon chain of at least 30 carbon atoms and preferably of at least 50 carbon atoms find use as detergents in lubricating oils.

The compounds of this invention have the formula:

A -s-n it 1 3.

wherein A is a long aliphatic hydrocarbon chain radical of at least 30 carbon atoms, preferably 50 carbon atoms, or a hydrocarbon radical of from 1 to carbon atoms, A is a long hydrocarbon chain of at least carbon atoms, preferably 50 carbon atoms, or hydrogen, or a hydrocarbon radical of from 1 to 10 carbon atoms, with the proviso that only one of A and A is a long hydrocarbon chain and A is a hydrocarbon radical of from 1 to 10 carbon atoms.

Generally, the compounds of this invention will have the following formula:

I QB

wherein R is an aliphatic hydrocarbon radical of from about 30 to 200 carbon atoms, preferably of from about 50 to 200 carbon atoms, and more preferably a branched hydrocarbon chain, R is hydrogen or lower alkyl, preferably hydrogen and R is a hydrocarbon radical of from 1 to 10 carbon atoms, preferably a hydrocarbon radical of from 1 to 6 carbon atoms, e.g., lower alkyl or phenyl. R may be aliphatic, aromatic, alicyclic or combinations States Patent 0 "Ice thereof, e.g., alkaryl and aralkyl, and may or may not have aliphatic unsaturation, e.g., olefinic.

The preferred compounds of this invention are of the following formula:

l NH

R CH3 wherein R is as defined previously.

In preparing the sulfoximines of this invention, a long chain hydrocarbon may be halogenated and the halogen displaced with the desired mercaptide. The sulfur may be substituted at a terminal or internal carbon atom. After oxidizing the resulting sulfide to the sulfoxide, the sulfoximine may then be prepared from the sulfoxide.

The long chain hydrocarbon group which has been designated as R or R can readily be prepared by polymerizing aliphatic olefins of from about 2 to 5 carbon atoms, i.e., ethylene, propylene, butene-l, isobutylene, pentene-l, etc., preferably, olefins of from 3 to 4 carbon atoms, particularly propylene and isobutylene.

The olefin prepared by the polymerization of the low molecular weight olefins may then be reacted with halogen, either bromine or chlorine, by ionic or free radical methods, to form the alkenyl halide. The halide is then reacted with the desired mercaptide to form the sulfide.

Methods for carrying out the halogenation and displacement are well known in the art and do not require extensive exemplification.

Generally, the alkali metal salt of the mercaptan is prepared either with the metal, metal hydride or hydroxide in a polar solvent and the solution of the alkali metal mercaptide contacted with the hydrocarbon halide in the presence of an inert solvent, e.g., benzene, at relatively mild temperatures-less than C.

The sulfide is readily transformed to thesulfoxide by oxidation with a peroxide, e.g., hydrogen peroxide. These methods are well known in the art.

The sulfoximine may then be prepared from the sulfoxide by reacting the sulfoxide with sodium azide in the presence of a strong mineral acid, e.g., concentrated sulfuric acid at ambient or slightly elevated temperatures. Usually, an inert solvent is used, such as chloroform. The method of preparation of the sulfoximine is found in Proceedings of the Royal Society, London, Series B, vol. 138, pp. 265-272, 1951.

Illustrative of various compounds of this invention are polyisobutenyl methyl sulfoximine, polyethylenyl methyl sulfoximine, polypropenyl methyl sulfoximine, polyisobutenyl ethyl sulfoximine, polyisobutenyl phenyl sulfoximine, polyisobutenyl hexyl sulfoximine, polyisobutenyl propyl sulfoximine, polyisobutenyl cyclopentyl sulfoximine, etc. (The polyalkenyl groups can be either saturated or unsaturated, having olefinic unsaturation and are from about 30 to 200 carbon atoms.)

The following examples are offered by way of illustration and not by way of limitation.

EXAMPLE A Exemplary preparation of polyisobutenyl bromide Into a reaction flask was introduced 1,350 g. of polyiso'butene (1.5 moles, approximately 900 molecular weight) as a 48 weight percent solution in oil, the mixture cooled to about C. and a solution of 240 g. (1.5 moles) of bromine in 750 ml. of carbon tetrachloride added over a period of 4 hours, while maintaining the temperature below 10 C. The mixture was then allowed to warm to room temperature with stirring and the sOlVent removed by heating to 100 C. at a temperature of 10 mm. Hg. The residue was then analyzed for bromine.

Analysis.Wt. Percent Br=9.46.

EXAMPLE B Exemplary preparation of polyisobutenyl methyl sulfide Into a reaction flask was introduced 162 g. (2.4 moles) of a 95 weight percent aqueous potassium hydroxide solution and then diluted with 500 ml. of absolute ethanol. The solution was cooled with an ice bath, the flask fitted with an acetone-dry ice condenser and then 106 g. (2.4 moles) of methyl mercaptan added to the solution. To the resulting potassium methyl mercaptide was added 1,267 g. (1.2 moles, approximately 93 weight percent of the bromide) of polyisobutenyl bromide (prepared as described in Example A) in 1 liter of benzene. The addition of the benzene solution was at a rate which maintained the temperature below 36 C. After all of the benzene solution was added, the mixture was stirred and then refluxed overnight.

The benzene phase was then separated from the ethanolic phase, washed with water until neutral and then dried over sodium sulfate. The benzene was stripped in vacuo yielding 995 g.

Analysis.-Wt. Percent 8:2.55; Wt. Percent Br: 0.727.

EXAMPLE C Exemplary preparation of polyisobutenyl methyl sulfoxide Charged to a reaction vessel was 942 g. (0.995 mole) of polyisobutenyl methyl sulfide (approximately 1,000 molecular weight), 1 liter of benzene, 50 cc. of glacial acetic acid and then slowly with stirring 169 g. of weight percent hydrogen peroxide. The reaction was cooled to maintain the temperature at about room temperature. At the end of the addition, the reaction mixture was diluted with ether and thoroughly washed with water to remove acid. The reaction mixture was then dried and the solvents removed in vacuo. Yield=960 g.

Analysis.--Wt. Percent 8:198; molecular weight (thermo-NAM) =975.

EXAMPLE 1 Into a reaction vessel was introduced 500 g. of material prepared in Example C and 1 liter of chloroform. To this mixture was slowly added with stirring 200 ml. of concentrated sulfuric acid, resulting in a rise in temperature. When the mixture had returned to room temperature, 39 g. (0.6 mole) of sodium azide was then added slowly over a 1 hour period. Upon completion of the addition, the temperature was raised to C. and maintained there for 1 hour. The following day half of the material was transferred to a separatory funnel and washed with water. The material was then dried over anhydrous sodium sulfate and the solvent stripped in vacuo. The yield from the aliquot was 168 g.

Analysis.-Wt. Percent N=0.'53, 0.55; Wt. Percent S: 2.05, 2.06.

The above procedure was repeated with 400 g. (0.4 mole) of the same polyisobutenyl methyl sulfoxide provicling 376 g. of the sulfoximine product. This material was combined with the above material.

EXAMPLE 2 Into a reaction vessel was introduced 1,005 g. (2.25 moles) of polyisobutenyl methyl sulfide (approximate molecular weight=447), 1 liter of benzene, 150 ml. of glacial acetic acid and then 360 g. (3.38 moles) of 30 weight percent aqueous hydrogen peroxide added slowly. The reaction mixture was Worked up as previously described, yielding 1,021 g. of polyisobutenyl methyl sulfoxide.

Analysis. Wt. Percent S=3.40; molecular weight (thermo-NAM) :438.

The above material was diluted with 1 liter of chloroform and then 300 ml. of concentrated sulfuric acid added with cooling. To the mixture was added 282 g. (4.34 moles) of sodium azide resulting in some foaming. The sodium azide was added at a rate which maintained the temperature at approximately 35 C., requiring some cooling with a water bath. Upon completion of the addition of the sodium. azide, the reaction mixture was maintained at 35 C. overnight. The reaction mixture was then diluted with pentane, washed freely with water until neutral to pH paper and dried over anhydrous sodium sulfate. The solvents were stripped in vacuo at C. The yield=595 g.

Analysis-Wt. Percent S=2.9; Wt. Percent N=1.22, 1.22; Wt. Percent Br=0.37; molecular weight (thermo- NAM)=595.

As already indicated, the compounds of this invention find use as dispersants and detergents in lubricating oils. They are of particular value in diesel engines, demonstrating excellent results under the high temperatures at which diesel engines operate. When compounded with a lubricating oil for use in an engine, the compounds of this invention will be present at least about 0.1 weight percent and usually not more than 15 weight percent, more usually in the range of about 1 to 10 weight percent.

The compounds can be prepared as concentrates, due to their excellent compatibility with oils. As concentrates, the compounds of this invention will generally range from about 10 to 70 weight percent, more usually from about 20 to 50 weight percent of the total composition.

A preferred aspect in using the compounds of this invention in lubricating oils is to include in the oil from about 6 to 50 mm./kg. of zinc 0,0-dihydrocarbyl phosphorodithioate, wherein the hydrocarbyl groups are from about 4 to 36 carbon atoms. Usually, the hydrocarbyl groups will be alkyl or alkaryl groups. Other phosphorodithioates may also be used with advantage.

The lubricating fluids which may be used with the compounds of this invention (hereinafter referred to as oils) may be derived from natural or synthetic sources. Oils generally have viscosities of from about 35 to 50,000 Saybolt Universal Seconds (SUS) at F. Among natural hydrocarbonaceous oils are paraffin base, naphthenic base, asphaltic base and mixed base oils. Illustrative of synthetic oils are: hydrocarbon oils, such as polymers of various olefins, generally of from 2 to 8 carbon atoms, and alkylated aromatic hydrocarbons; and nonhydrocarbon oils, such as polyalkylene oxides, aromatic ethers, carboxylate esters, phosphate esters and silicon esters. The preferred media are the hydrocarbonaceous media, both natural and synthetic.

The above oils may be used individually or together, whenever miscible or made so by the use of mutual solvents.

Other additives may also be included in the oil such as pour point depressants, oiliness agents, antioxidants, rust inhibitors, etc. Usually, the total amount of the additives will range from about 0.1 to 10 weight percent, more usually from about 0.5 to 5 weight percent. The individual additives may vary from about 0.01 to 5 weight percent.

In order to demonstrate the excellent effectiveness of the compounds of this invention as detergents and dispersants in lubricating oils, the exemplary compound prepared in Example 1 was tested in the 1-G Caterpillar Test (MILL-45199 conditions. The oil used was a Mid-Continent SAE 30 oil and 12 mm./kg. of zinc di(alkylphenyl) phosphorodithioate (the alkyl groups were polypropylene of about 12 to 15 carbon atoms) was included. Five weight percent of the detergent was used and the test was carried out for 60 hours.

The land deposits are rated on a scale of 0 to 800; 0 is completely clean and 800 is completely black. Base oil containing the indicated amount of phosphorodithio-ate is rated as 500800330. The groove deposits are rated on a scale of 0 to 100; O is completely clean and 100 is completely black. Base oil containing the indicated amount of phosphorodithioate is rated as 93155-3. The underhead deposits are rated on a scale of 0 to 10; 0 is completely black, while 10 is completely clean.

The results of the Caterpillar performance were groove deposits: 60 10-0; land deposits: 2004-0; underhead deposits: 7.5.

It is obvious from the above results that the sulfoximines are excellent detergents under the extremely severe high temperatures at which diesel engines are operated. Moreover, the detergents are compatible with a common additive, namely the phosphorodithioate.

As will be evident to those skilled in the art, various modifications on this invention can be made or followed, in the light of the foregoing disclosure and discussion, without departing from the spirit or scope of the disclosure or from the scope of the following claims.

6 I claim: 1. A composition of the formula:

0 R l-R wherein R is a polyolefin of an olefin of from 3 to 4 carbon atoms and having a total of from about 50 to 200 carbon atoms.

3. A composition according to claim 2 wherein R is polyisobutylene.

References Cited UNITED STATES PATENTS 8/1953 Reiner et al. 260-551 12/1962 Berry 260-551 JOHN D. RANDOLPH, Primary Examiner.

WALTER A. MODANCE, N. S. MILESTONE,

Examiners. H. MOATZ, Assistant Examiner. 

